Electric switch contact assembly



Allg- 4, 1953 H. E. scHLl-:lcHER 2,647,974

ELECTRIC swTTcH CONTACT ASSEMBLY Filed Deo. l, 1950 l lig-l; 5

. l @I @'36 W/ @j 6@ A 67:5 :OB 39: O 64 o l 'I' 'l 0 0 '23@ L'" O 3 Il g I1 enfor- @Horne/:52

Patented Aug. 4, 1953 ELECTRIC SWITCH CONTACT ASSEMBLY Harold E. Schleicher, West Hartford, Conn., as-

signor to The Arrow-Hart & Hegeman Electric Company, Hartford, Conn., a corporation of Connecticut Application December 1, 1950, Serial No. 198,680

7 Claims. (Cl. 20D-166) This invention relates to an improved contact assembly for an electric switch and is particularly useful in electro-magnetically operated switches but its use is not limited thereto.

In switches wherein the pair of Xed contacts are adapted to be connected by a movable bridging contact, the condition of the contacts is usually normally-closed or normally-open. Often it is desired to change the relation from normally-closed to normally-open and viceversa. This need may occur after the switch has been assembled and perhaps has been sold and put in service; or it may occur before assembly by reason of a customers order specifying certain contact relationships.

Various means have heretofore been provided for reversing both the lixed contacts and the movable bridging contact requiring at least three manual manipulations, since each of the two xed contacts would have to be reversed or interchanged and the movable contact would also have to be reversed.

It is an object of the present invention to provide a Contact assembly wherein only the fixed contacts need be reversed or interchanged in order to change the switch from a normallyopen to a normally-closed condition or viceversa.

Another object of the invention is to provide an assembly to accomplish-the foregoing objective wherein the contacts are interchangeable in order to reduce the cost of tools and to lower manufacturing costs and inventories.

Another object is to provide a contact assembly of the foregong type in which the parts may be economically manufactured and assembled or reassembled, without sacricing quality or reliability of operation.

Other objects and advantages of the invention will become apparent as it is described in connection with the accompanying drawing.

In the drawing:

Fig. l is a plan view of two poles of an electromagnetic switch embodying the invention.

Fig. 2 is an end elevation view of the structure of Fig. l, partly in section along line 2-2 of Fig. l.

Fig. 3 is an enlarged section view of the movable contact member and mounting, taken along line 3-3 of Fig. l.

Fig. l is a section view similar to Fig. 3 of another form of movable contact mounting.

Referring to the drawing, the invention is described for convenience as applied to an electromagnetically operated switch but it will be understood that the invention is not limited to such use since any other operating means might be employed as well. A conventional electromagnetic operating means is mounted upon the base plate I0 and includes a pivoted movable armature member I2 in a metal frame member I4. The armature is pivotally mounted about a pin I6 in the frame member I4 and has an arm I8 attached thereto which in turn is pivotally mounted at its end by a pin 20 to a movable contact carrier 22. Upon the movable contact carrier are mounted upper and lower insulating bars 24 and 25 which extend transversely across the switch. The bar 26 lies on top of the bar 24 and is of similar shape and dimension. The two bars may be secured together upon the supporting member 22 by bolts 28 spaced therealong.

The contact supporting bars 24 and 26 move within a recess shaped and provided for that purpose transversely in a base member 30 which may be made of molded insulation or other suitable insulating material.

Mounted at opposite sides of the insulating base member 3B on the top face thereof are fixed contact members 32 and 34. These contacts may be stamped from sheet metal to provide each with a terminal or mounting portion such as B2i and 34t lying upon the top surface of the insulating base 30 and secured thereon by screw bolts 33. Each may also have a contact portion 32o and 34o offset from the terminal portion in a downward direction as illustrated in full lines in Fig. 2. On the upper surface of these Contact portions, conventional contact buttons 32h and. 34h of good conducting material may be provided for engagement with similar contact buttons on a movable bridging contact member 40 described below.

The bridging contact 46 may be stamped from thin resilient sheet metal such as Phosphor bronze, copper or other highly conductive resilient material in the form of a strip. The strip is mounted transversely between the upper and lower` insulating bars 24 and 26 on a contact carrier in the following manner. The adjacent surfaces of the insulating bars 24 and 26 are recessed transversely at spaced points to provide spaced passageways 42 through which a series of bridging contacts pass, one for each set of stationary contacts like 32, 34. Pressing against the upper and lower surfaces respectively of the bridging contact at its central portion are opposite identical cylindrical sleeve members 44 and 45. VThese sleeve members are adapted to slide within cylindrical bores 46 and 41 in the insulating bars 24 and 26. Seated against the bottom of each bore is a coiled compression spring 48 and 49, whose opposite end presses against the peripheral edge of the sleeve member which is within the bore, thus urging the members 44, 45 oppositely against the opposite sides of the bridging contact.

Necks B and 5| of reduced diameter are formed on the inner ends of each of the sleeves 44 and 45 around the central portion of identical anchor members 52, 53. These central portions are substantially cylindrical and are hollow to receive the opposite ends of a round guide rod 55 which is coaxial with the sleeve members 44 and 45 and passes through a hole in the middle of the bridging contact 49. The inner ends 54 of the anchor members are reduced in diameter and screw threaded to t within bores or cylindrical recesses coaxial with and in the bottoms of the larger bores 46, 4'! in the insulating members 24 and 26. In this way the anchor members 52 and 53 are frictionally held in place upon the insulating bars 26 and 24 respectively. In order to prevent the springs 48 and 49 from pressing the sleeve members 44 and 45 off of the anchor members 52 and 53 during assembly, a flange 56 is provided upon the proximate ends of each of the anchor members 52 and 53. These anges lying within the sleeve members adjacent their necks 5), 5| prevent the sleeves from moving o the anchor members while the two bars 24, 25 are being joined.

From the foregoing, it may be observed that the anchor members supply the means to mount the sleeve members upon the insulating bars 24 and 26 and the springs 46 and 49 press the sleeve members toward each other and against the opposite surfaces of the bridging contact member 49.

In this way, the bridging contact member 40 is i supported floatingly by the springs 48, 49. When the contact buttons on its ends engage the contact buttons on the fixed contact members 32 and 34 the bridging contact is permitted to move within the recess 42 between the insulating bars 24 and 26 to adjust itself and to maintain contact engagement and pressure,

Upon energization of the electromagnet, the armature |2 through the arm |8 and carrier member 22 will cause upward movement of the contact carrier bars 24 and 26 and will move the bridging contact away from the xed contacts after the bridging contact has come to its mid-position as the action of the compression springs 48 and 49 equalizes. During such movement, the bridging contact is guided by the guide rod 55 which also acts to hold the movable contact against movement endwise while permitting tilting movement due to the loose t of the guide rod in the hole of the contact.

Alongside of the xed contacts 32 and 34 are or may be mounted a second set o xed contacts 62 and 64 of identical form to the xed contacts 32 and 34. These contacts 62 and 64 however are mounted (as shown in dotted lines in Figs. 2 and also in plan in Fig. 1) so that their onset portions 62D, 64b extend upwardly or in other words are located in a plane above the terminal portions 62t and 64t which rest on the upper surface of the insulating base 39 in the same plane as 32t and 34t. Extending between the fixed contacts 62 and 64 is a bridging contact 4| exactly like bridging contact 49 and mounted in the same as the bridging contact 40; but the contact buttons on the upper surface engage the fixed contacts 62, 64 whereas the buttons on the lower surface engage contacts 32, 34. It will be observed however that due to the way these xed contacts 62 and 64 are mounted, the bridging contact 4| will be normally disengaged from them when the bridging contact is engaged with the contacts 32 and 34. It will now be apparent that if it should be desired to have the fixed contacts 62 and 64 normally engaged by the bridging contact 4|, it is only necessary to invert those contacts and reverse their positions, i. e. putting the contact 62 in place of the contact 64 while turning it up side down and vice-versa. And the same applies to contacts 32 and 34 if it should be desired to have them normally disengaged from the bridging contact 40. The oating mounting of the bridging contact enables proper contact engagement and pressure regardless Whether the xed contacts are mounted for normally-open or normally-closed conditions.

In the drawing of Fig. l, the xed contacts are shown as having their contact portions angularly displaced with relation to the terminal portions but this is not essential. The terminal contact portions could be in alignment if desired.

In Fig. 4 wherein like reference numerals indicate like parts in Fig. 3, I have illustrated another form of mounting for the movable contact member. In this form the bars 24 and 26 forming the movable contact carrier have bores 46 and 41 and a recess 42 at their adjacent surfaces as before. In this form however the movable contact guide rod |55 has its ends received within borings similar to those which received the end portions of the anchor members in the previously described form. The mid-portion of the guide rod |55 is enlarged as at |56 and the hole in the bridging contact |46 is likewise enlarged to accommodate the enlarged portion |56. Sleeve members |44, |45 have anges |57, |53 Whose proximate surfaces press against opposite sides of the bridging contacts |40, while the opposite sides or" the flanges form seats for the springs 4B and 49.

In each of the forms of mounting for the bridging contact member if it should happen that the movement of the movable contact supporting bars 24 and 26 exceeds the limit of movement permitted by the recess 42, the resilience of the contacts themselves will permit some additional movement. Thus, not only do the springs 46 and 49 permit the bridging contact to accommodate itself in engaged position to the xed contacts but also the resilience of the bridging contacts will permit some overtravel.

From the foregoing, it may be observed that I have provided a contact assembly and mounting wherein normally engaged fixed and bridging contacts may be readily converted to normally disengaged condition by only transposing and inverting the fixed contact on one side with the xed contact on the other side of any set. Moreover, the xed contacts of any set are interchangeable with any other set as are also the bridging contacts.

Many modications within the scope of the invention will occur to those skilled in the art. Therefore I do not limit the invention to the exact form and detail as illustrated and described.

What is claimed is:

l. In an electric switch, a bridging contact movable to engage and disengage xed contacts, a movable carrier for said bridging contact oomprising cooperating insulating members beyond which said bridging contact extends, a passage between said members at their cooperating faces in which said bridging contact is located and movable, sleeve members on opposite sides of said bridging contact, and spring means between each insulating member and sleeve member pressing said sleeve members against said bridging contact on opposite sides thereof whereby said contact is floatingly mounted, and a guide member running between said insulating members and through said bridging contact guiding the movement of said bridging contact.

2. In an electric switch as claimed in claim 1, means engaging said sleeve members to movably secure them to their respective insulating members against the stress of said spring means `during assembly.

3. An electric switch as claimed in claim l. anchor members attached to each insulating member each having a flanged portion holding a sleeve member movably on its insulating member against the stress of said spring means during assembly.

4. An electric switch as claimed in claim l, wherein the guide member comprises a rod having its opposite ends in said insulating members, and an enlarged mid-portion within and guiding the movement of said sleeve members and said movable contact.

5. An electric switch as claimed in claim 4 having means to limit the movement of each sleeve member by the spring means which engages it, whereby that spring means becomes ineiective while the opposite spring means becomes compressed during contact engagement.

6. In an electric switch as claimed in claim 1J means engaging said sleeve members to movably secure them to their respective insulating members against the stress of said spring means, and means to limit the movement of each sleeve member by the spring means which engages it, whereby that spring means becomes ineffective while the opposite spring means becomes compressed during contact engagement.

7. An electric switch as claimed in claim 1, anchor members attached to each insulating member each having a flanged portion holding a sleeve member movable on its insulating member against the stress of said spring means, and means to limit the movement of each sleeve member by the spring means which engages it, whereby that spring means becomes ineffective while the opposite spring means becomes compressed during contact engagement.

HAROLD E. SCHLEICHER.

References Cited in the 111e of this patent UNITED STATES PATENTS Number Name Date 1,307,189 Downes et a1 June 17, 1919 1,928,846 Allen Oct. 3, 1933 2,109,299 VanValkenburg Feb. 13, 1940 2,562,420 Furnas July 31, 1951 2,583,139 Ellis Jan. 22, 1952 FOREIGN PATENTS Number Country Date 418,767 Great Britain Oct. 31, 1934 

